Battery question.....

[ajdedo]

Hi,

I got my x200s with a 9 cell battery back in March. It was great with 12+ hours consistently. All of a sudden, about 2 or 3 weeks ago, I notice that fully charged it will only give me 6 hours at best. What happened? How can it go from 12 to 6 hours in what seems like overnight?

Thanks.....

[dr_st]

In the Power Manager you can check the "Full Charge Capacity" of the battery versus the "Design Capacity". If the former is substantially lower than the latter, then the battery life will be equally shorter, compared to a new battery.

However, these things usually don't happen overnight. My guess would be that the battery is just fine and still in the same condition, but one of two things happened:

1) Your power management scheme somehow changed and the CPU doesn't switch to lower frequency while idling. A tool like Notebook Hardware Control (NHC) or CPU-Z can help you check that.

2) There is some pesky background process running all the time (or a large percentage of the time), preventing the CPU from idling. Monitoring using the Process Manager (Ctrl+Shift+Esc) can help you detect such a process.

In any case, you can set the power manager to display wattage consumption instead of time remaining, while running on battery. My bet is that it would be substantially higher than normal.

[ajdedo]

1) It's possible, I was messing around with that at one point, but I thought I left it the same as it was originally.

2) Nothing suspicious in Task manager. System Idle Process is bouncing around 94%

3) The notebook is rather new, so I haven't had time to get familiar with what is "normal", but it does seem to me that the fan may be staying on longer and/or louder.

4) Battery Stats are ->

Design Capacity - 84.24 Wh
Full Charge Capacity - 80.14 Wh
Cycle Count - 57
Current - 1.24 Amp
Wattage - 15 Watts

5) I have CPU-Z, but I'm unsure what to look for.

Thanks!

[dr_st]

A simple calculation shows that at 15Watts, and 80.14Wh capacity, you'll get about 5:20 runtime.

15W for such a laptop while idling is much higher than I would expect. I get around that on my T60.

In CPUZ you should just look at the CPU frequency, which is updated in real-time.

While idling, I'd expect the frequency to be stuck at the minimum. If you see that from some reason it's stuck at the maximum, then there is likely a problem with the power management. If it constantly jumps between min and max, I'd say it's some pesky process.

If there is no pesky process, and the CPU clock is at the minimum, it can be power consumption from one of the other peripheral devices (USB/BT/Wifi). Sometimes bugs in the drivers cause USB to consume much more power than needed.

[ajdedo]

Yeah, 5:20 is about what I get, last month I was getting 12 hrs!

The CPU freq seems to jump back and forth between 1596 and 1862 for some reason, but task manager does seem to offer any insight. I guess I'll just have to start killing processes until my CPU speed drops to the min. But would that really make a 6 hour difference? And what about the fan speed?

[dr_st]

I find 12 hours a little difficult to believe... It would mean that the _average_ power consumption was just 7 watts. The only way you would get that is if everything was turned off, screen was dimmed at you didn't do anything with the computer except just staring at it.

[ajdedo]

Almost true.

It usually said 12 hours when I just turned on the computer (screen full brightness). After I started using the computer for a while, it would drop to 11, 10 and even 8 after an hour or so of use.

But my point is, that even after an hour of use, if I restarted it, or put it in and out of standby, the power meter would bounce back up to at least 11 when it was turn on again. (even if it didn't stay there for too long).

But now, the meter won't go past 6 at full charge at first start-up, and quickly drops to 5.

[Harryc]

It sounds to me like your battery was not initially calibrated properly... and now it is.